1. Technical Field
The present invention relates to a paper sheet binding die set capable of binding a plurality of paper sheets without use of metal staples, glues, strings, cords, or the like.
2. Background Art
Conventionally, many booklets and ledger sheets are created by binding with use of metal staples, glues, or the like. In a case of using the metal staples for binding, however, when a bound state is incomplete, there is a risk that end portions of the metal staple protrude.
Further, regarding disposal of booklets and ledger sheets that have become unnecessary, the booklets and ledger sheets are shredded by a shredder when necessary and then incinerated, or reused as recycled paper sheets in terms of resource conservation. In this context, in order to avoid damage to blades of the shredder, it is necessary to remove metal staples from paper sheets bound with the metal staples. Further, regarding paper sheets bound with glue, when the glue is a resin-based glue such as a hot-melt glue, it is necessary to cut off glued parts of the paper sheets so that noxious gases are not generated at the time of incineration.
Those operations require time and effort, which is reflected in costs such as a personnel cost. In order to overcome the problem, in other words, in order to bind paper sheets without use of metal staples or glues, for example, there have been disclosed a binding method and a binding apparatus in which, at the time of binding a plurality of paper sheets such as ledger sheets, moisture is supplied to each of the paper sheets, and then pressure is applied from above and below by binding members respectively provided with a series of projections and recesses (for example, refer to JP 3481300 B and JP 3502204 B).
However, by the binding method according to the technologies disclosed in Patent Literature 1 and Patent Literature 2, in which moisture is supplied to each of the paper sheets, and then pressure is applied from above and below by binding members respectively provided with a series of projections and recesses, bound parts are corrugated owing to the moisture. Thus, the method is not applicable to aesthetic articles such as a booklet and a brochure, and hence application of the method is limited to ledger sheets and the like. Further, in order to evenly supply moisture with respect to each of the paper sheets separately, it is necessary to install an elaborate and complex device for a preceding step of a binding process. Thus, in order to bind a large number of paper sheets, a scale of the device becomes larger in accordance therewith. Those are problems with this method.